[WebAssembly] Define a table of function signatures for runtime library calls.

LLVM CodeGen emits references to external symbols that are never declared in
LLVM IR level, so they have no declared signature. However, WebAssembly requires
all functions be declared with signatures. This patch adds a table for providing
signatures for known runtime libcalls that will be used in subsequent patches to
emit declarations for such functions.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@295857 91177308-0d34-0410-b5e6-96231b3b80d8

lib/Target/WebAssembly/CMakeLists.txt

@@ -35,6 +35,7 @@ add_llvm_target(WebAssemblyCodeGen
   WebAssemblyRegNumbering.cpp
   WebAssemblyRegStackify.cpp
   WebAssemblyReplacePhysRegs.cpp
+  WebAssemblyRuntimeLibcallSignatures.cpp
   WebAssemblySelectionDAGInfo.cpp
   WebAssemblySetP2AlignOperands.cpp
   WebAssemblyStoreResults.cpp

lib/Target/WebAssembly/WebAssemblyRuntimeLibcallSignatures.h

@@ -0,0 +1,38 @@
+// CodeGen/RuntimeLibcallSignatures.h - R.T. Lib. Call Signatures -*- C++ -*--//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+///
+/// \file
+/// \brief This file provides signature information for runtime libcalls.
+///
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_LIB_TARGET_WEBASSEMBLY_RUNTIME_LIBCALL_SIGNATURES_H
+#define LLVM_LIB_TARGET_WEBASSEMBLY_RUNTIME_LIBCALL_SIGNATURES_H
+
+#include "llvm/ADT/SmallVector.h"
+#include "llvm/CodeGen/RuntimeLibcalls.h"
+#include "MCTargetDesc/WebAssemblyMCTargetDesc.h"
+
+namespace llvm {
+
+class WebAssemblySubtarget;
+
+extern void GetSignature(const WebAssemblySubtarget &Subtarget,
+                         RTLIB::Libcall LC,
+                         SmallVectorImpl<unsigned> &Rets,
+                         SmallVectorImpl<unsigned> &Params);
+
+extern void GetSignature(const WebAssemblySubtarget &Subtarget,
+                         const char *Name,
+                         SmallVectorImpl<unsigned> &Rets,
+                         SmallVectorImpl<unsigned> &Params);
+
+} // end namespace llvm
+
+#endif